A number of prokaryotic proteins involved in cell cycle processes have been found [1,2] to be structurally related, these proteins are:

• Escherichia coli and related bacteria cell division protein ftsW. This protein plays a role in the stabilization of the ftsZ ring during cell division.
• Escherichia coli and related bacteria rod shape-determining protein rodA (or mrdB). It is required for the expression of the enzymatic activity of PBP2, which is thought to participate in the synthesis of peptidoglycan during the initiation of cell elongation.
• Bacillus subtilis stage V sporulation protein E (spoVE). The exact function of spoVE in endospore formation is not known.
• Bacillus subtilis hypothetical protein ylaO.
• Bacillus subtilis hypothetical protein ywcF (ipa-42D).
• Cyanophora paradoxa cyanelle ftsW homolog. This protein may be involved in the organelle division process.

All these proteins are hydrophobic integral membrane protein and contain about 400 residues. We have selected the best conserved region, which is located in the C-terminal section, as a signature pattern for these proteins.